Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Transmission control
Reexamination Certificate
1998-07-31
2001-01-09
Cuchlinski, Jr., William A. (Department: 3664)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Transmission control
C701S050000, C192S220100
Reexamination Certificate
active
06173228
ABSTRACT:
TECHNICAL FIELD
This invention relates to a machine having an electronically controlled transmission, and more particularly, to a method and apparatus for controllably engaging, and disengaging, a neutralize mode associated with the transmission.
BACKGROUND ART
Often, in machines, such as small wheel loaders, a neutralize function enables the transmission to be shifted to neutral when the service brakes are applied. In prior systems, the neutralize function typically utilizes an on/off limit switch. The limit switch is usually located beneath a service brake pedal. As the service brake pedal is depressed, the travel limit for the limit switch is reached, inducing the limit switch contacts to close. The closed state of the limit switch contacts is communicated to an electronic controller associated with the machine, and a signal for brake actuation is subsequently produced.
A problem with this form of engaging and disengaging a neutralize function is the nonspecific amount of brake pedal travel that may occur prior to the brakes being applied. As a result of the nonspecific amount of brake pedal travel, the transmission may be neutralized at an undesirable time. If, the transmission is neutralized later than desirable, premature wear on the break pads may occur due to the service brakes being applied prior to the transmission being placed in neutral. Also, excessive wear on the service brakes occurs if the transmission is neutralized sooner than desirable.
Also, due to wear of mechanical parts and lack of proper maintenance, the brake pedal travel distance may alter. If, the brake pedal travel distance alters, the enabling time of the neutralize function could alter.
The present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, a method of controlling a transmission included in a machine is disclosed. The machine has a controller and a brake system. A neutralize pressure value is established, and a system brake pressure associated with the brake system is determined. A comparison is made between the system brake pressure and the neutralize pressure value, and a neutralize mode associated with the transmission is responsively engaged.
In another aspect of the present invention, a method of controlling a transmission included in a machine is disclosed. The machine has a controller and a brake system. A in gear pressure value is established, and a system brake pressure associated with the brake system is determined. A comparison is made between the system brake pressure and the in gear pressure value, and a neutralize mode associated with the transmission is responsively disengaged.
In a third aspect of the present invention, a machine having a controllable transmission, is disclosed. The machine has a brake system. Associated with the machine is a controller configured to communicate with the transmission and the brake system. A neutralize pressure value is stored in a memory device, associated with the controller. Also, associated with the brake system is a pressure sensor configured to sense a system brake pressure. A neutralize mode, associated with the transmission, is configured to be controllably engaged.
In a fourth aspect of the present invention, a machine having a controllable transmission, is disclosed. The machine has a brake system. Associated with the machine is a controller configured to communicate with the transmission and the brake system. A in gear pressure value is stored in a memory device, associated with the controller. Also, associated with the brake system is a pressure sensor configured to sense a system brake pressure. A neutralize mode, associated with the transmission, is configured to be controllably disengaged.
In a fifth aspect of the present invention, a system for controlling a transmission on a machine is disclosed. A brake system is located in the machine. Associated with the machine is a controller configured to communicate with the transmission and the brake system. A memory device, associated with the controller, stores a neutralize pressure value. Also, associated with the brake system is a pressure sensor configured to sense a system brake pressure. A neutralize mode is configured to be engaged in response to a comparison of the system brake pressure and the neutralize pressure value.
In a sixth aspect of the present invention, a system for controlling a transmission on a machine is disclosed. A brake system is located in the machine. Associated with the machine is a controller configured to communicate with the transmission and the brake system. A memory device, associated with the controller, stores a in gear pressure value. Also, associated with the brake system is a pressure sensor configured to sense a system brake pressure. A neutralize mode is configured to be disengaged in response to a comparison of the system brake pressure and the neutralize pressure value.
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Carlson Robert D.
Hayward Randy R.
Rubin Laurence M.
Ufheil Steven T.
Buck Byron G.
Caterpillar Inc.
Cuchlinski Jr. William A.
Gibson Eric M.
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